Preparation method of protective coating for battery box

Abstract

The invention discloses a preparation method of a protective coating for a battery box, which comprises the following steps: dissolving a block copolymer brush with a side chain containing PDMS (Polydimethylsiloxane) and PS (Polystyrene) in cyclohexane, so that the block copolymer brush with the side chain containing PDMS and PS is self-assembled to form microspheres, and the protective coating for the battery box is obtained. The protective coating for the battery box prepared by the invention can reflect light with wavelength in a specific range through the photonic crystal, so that heat absorption of the battery box is reduced, and the thermal management efficiency of a battery is improved. According to the preparation method, the three-dimensional spherical photonic crystal is prepared through soft limited assembly, and the preparation method is simple and low in energy consumption. By regulating the molecular weight / polymerization degree of the segmented copolymer brush with the side chain containing PDMS and PS, the particle size of the microspheres can be regulated, so that photonic crystals with different reflection wavelengths are obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power, and in particular relates to a method for preparing a protective coating for a battery box. Background Art

[0002] Energy storage, as an important component of building a new power system, is crucial to achieving the dual carbon goals. At present, the installed capacity of electrochemical energy storage has increased year by year, and it occupies an important position in the entire energy storage field. Among them, outdoor energy storage is mostly in the form of prefabricated cabins in series and parallel. The operation of energy storage, that is, the service life, is closely related to the external environment. Most centralized outdoor energy storage is built in the sparsely populated northern or northwest regions, where the temperature difference between day and night is large. Especially in hot weather, the sunlight will cause the prefabricated cabin to absorb heat and the temperature will rise sharply, thereby increasing the difficulty of thermal management inside the container and increasing energy consumption.

[0003] Photonic crystals are periodic structures formed by materials with different dielectric constants alternating in space. They can effectively control the direction of light propagation and have broad application prospects in many fields such as visual sensors, reflective outdoor displays, structural color coatings and printing and dyeing, anti-counterfeiting identification, green printing, photocatalytic enhancement, photovoltaic cells, etc. Among them, three-dimensional photonic crystals are more generally practical than one-dimensional and two-dimensional photonic crystals because they can produce a complete photonic bandgap in all directions. Monodisperse colloidal microsphere ions are the basic units for constructing three-dimensional photonic crystals. The most common monodisperses can be divided into organic polymers and inorganic ones. Compared with inorganic microspheres, organic monodisperse polymer microspheres have the advantages of richer varieties, relatively simple preparation methods, and low costs.

[0004] Applying organic monodisperse polymer microsphere photonic crystals as a coating on the surface of the battery box can effectively prevent the temperature inside the battery box from rising due to light, thereby reducing the energy consumption of the system. Existing three-dimensional photonic crystals are usually prepared by gravity deposition, vertical sedimentation, pulling and liquid-liquid extraction. These preparation methods generally have the disadvantages of long assembly time, high preparation cost and complex operation, which are not conducive to large-scale production and difficult to apply to the preparation of battery box coatings. Summary of the invention

[0005] Therefore, the present invention provides a method for preparing a protective coating for a battery box, and prepares a photonic crystal battery box coating at a low cost.

[0006] To this end, the present invention provides the following technical solutions.

[0007] A method for preparing a protective coating for a battery box comprises the following steps: Dissolving a block copolymer brush containing PDMS and PS in a side chain in cyclohexane, so that the block copolymer brush containing PDMS and PS in a side chain self-assembles to form microspheres, thereby obtaining the protective coating for a battery box; The structural formula of the block copolymer brush containing PDMS and PS in the side chain is:

[0008] Wherein x is selected from an integer of 120 to 300, y is selected from an integer of 90 to 250, and the ratio of x to y is 1:0.5 to 2.

[0009] Optionally, the concentration of the block copolymer brush containing PDMS and PS on the side chains in cyclohexane is 1-10 g / L.

[0010] Optionally, in the structural formula of the block copolymer brush containing PDMS and PS in the side chains, x=2.15, y=2.15.

[0011] Optionally, in the structural formula of the block copolymer brush containing PDMS and PS in the side chains, x=148, y=131.

[0012] Optionally, in the structural formula of the block copolymer brush containing PDMS and PS in the side chains, x=122, y=93.

[0013] Optionally, the particle size of the microspheres is 48~220nm.

[0014] The present invention also provides a protective coating for a battery box prepared by the above-mentioned method for preparing the protective coating for a battery box.

[0015] The present invention also proposes a method for preparing a battery box coating, comprising the following steps: coating the above-mentioned protective coating for the battery box on the surface of the battery box, and allowing cyclohexane to volatilize to form the battery box coating.

[0016] Optionally, the coating method is spraying.

[0017] Optionally, the protective coating for the battery box is applied to the surface of the battery box, allowed to evaporate naturally for 2 to 3 hours, and then dried.

[0018] Optionally, the drying is carried out by drying or freeze-drying.

[0019] Optionally, the thickness of the battery box coating is 0.2~1mm.

[0020] The present invention also provides a battery box coating prepared by the above-mentioned method for preparing the battery box coating.

[0021] The beneficial effects of the present invention are: The protective coating for the battery box prepared by the present invention can reflect light of a specific wavelength range through photonic crystals, reduce heat absorption of the battery box, and improve the thermal management efficiency of the battery. The preparation method of the present invention prepares three-dimensional spherical photonic crystals through soft constrained assembly, and the preparation method is simple and has low energy consumption. The present invention can adjust the particle size of the microspheres by adjusting the molecular weight / degree of polymerization of the block copolymer brush containing PDMS and PS in the side chain, thereby obtaining photonic crystals with different reflection wavelengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is the SEM picture of Example 1.

[0024] Figure 2 The SEM images of Example 2 and Example 3; Figure 2 (a) is the SEM image of Example 2. Figure 2 (b) is the SEM image of Example 3.

[0025] Figure 3 The SEM images of Comparative Example 1, Comparative Example 2 and Comparative Example 3 are shown; Figure 3 (a) is the coating surface diagram of Comparative Example 1, Figure 3 (b) is a cross-sectional picture of the coating of Comparative Example 1. Figure 3 (c) is the coating surface diagram of Comparative Example 2. Figure 3 (d) is a cross-sectional picture of the coating of Comparative Example 2. Figure 3 (e) is the coating surface diagram of Comparative Example 3. Figure 3 (f) is a cross-sectional picture of the coating of Comparative Example 3. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The materials used in the present invention are all commercially available products.

[0027] The applicant found in the process of studying the block copolymer brushes containing PDMS and PS in the side chains that when the block copolymer brushes are dissolved in cyclohexane, the block copolymer brushes will self-assemble to form microspheres, and a slightly turbid dispersion system will be obtained, which can be coated on a substrate to form a photonic crystal coating. However, when the block copolymer brushes are dissolved in other common solvents such as tetrahydrofuran and dichloromethane, microspheres cannot be formed.

[0028] Based on the above research results, the present invention discloses a method for preparing a protective coating for a battery box, comprising the following steps: dissolving a block copolymer brush containing PDMS and PS in side chains in cyclohexane, allowing the block copolymer brush containing PDMS and PS in side chains to self-assemble into microspheres, thereby obtaining the protective coating for the battery box.

[0029] The synthesis method of the block copolymer brush containing PDMS and PS in the side chains used in the present invention is shown in the reference: Morphologies and Photonic Properties of an Asymmetric Brush Block Copolymerwith Polystyrene and Polydimethylsiloxane Side Chains, Polymer 2018, 156, 169. The polymerization degree of gPDMS in the raw materials used is in the range of 120-300; the polymerization degree of gPS is in the range of 90-250; the molecular weight of the side chain PDMS is 3000, PDI=1.14; the molecular weight of PS is 2000, PDI=1.06.

[0030] Three block copolymer brushes containing PDMS and PS in the side chains were prepared by the above method: (gPDMS) 215 -b-(gPS) 215 The structural formula is as follows:

[0031] (gPDMS) 148 -b-(gPS) 131 The structural formula is as follows:

[0032] (gPDMS) 122 -b-(gPS) 93 The structural formula is as follows:

[0033] Example 1 Take 4g of (gPDMS) 215 -b-(gPS) 215Dissolve in 100 ml of cyclohexane and mix well to make the (gPDMS) 215 -b-(gPS) 215 The photonic crystal microspheres are self-assembled to obtain the protective coating for the battery box. The particle size of the photonic crystal microspheres is 190±30 nm as measured by a dynamic light scattering particle size analyzer.

[0034] The protective coating of the battery box is applied on a stainless steel substrate, and after the cyclohexane is volatilized, a coating is formed, and the coating thickness is 0.2 mm, thereby obtaining sample 1. The coating is observed under a scanning electron microscope (SEM). Figure 1 shown.

[0035] Example 2 Take 4g of (gPDMS) 148 -b-(gPS) 131 Dissolve in 80 ml of cyclohexane and mix well to make the (gPDMS) 148 -b-(gPS) 131 The photonic crystal microspheres are self-assembled to obtain the protective coating for the battery box. The particle size of the photonic crystal microspheres is 70±15 nm as measured by a dynamic light scattering particle size analyzer.

[0036] The protective coating of the battery box is coated on a stainless steel substrate, and after the cyclohexane is volatilized, a coating is formed, and the coating thickness is 0.2 mm, thereby obtaining sample 2. The coating is observed under a scanning electron microscope (SEM). Figure 2 As shown in (a).

[0037] Example 3 Take 4g of (gPDMS) 122 -b-(gPS) 93 Dissolve in 200 ml of cyclohexane and mix well to make the (gPDMS) 122 -b-(gPS) 93 The photonic crystal microspheres are assembled to obtain the protective coating for the battery box. The particle size of the photonic crystal microspheres is 51±3 nm as measured by a dynamic light scattering particle size analyzer.

[0038] The protective coating of the battery box is coated on a stainless steel substrate, and after the cyclohexane is volatilized, a coating is formed, and the coating thickness is 0.3 mm, thereby obtaining sample 3. The coating is observed under a scanning electron microscope (SEM), as shown in FIG. Figure 2 As shown in (b).

[0039] Comparative Example 1 Take 4g of (gPDMS) 215 -b-(gPS) 215Dissolve in 100 ml of tetrahydrofuran and mix evenly to obtain a protective coating. The protective coating of the battery box is coated on a stainless steel substrate. After the cyclohexane evaporates, a coating is formed with a thickness of 0.2 mm to obtain sample 4. The coating is observed under a scanning electron microscope (SEM). Figure 3 As shown in (a) and (b), wrinkled strips are formed on the coating surface, and the interior of the strips is porous, and spherical photonic crystals cannot be formed.

[0040] Comparative Example 2 Take 4g of (gPDMS) 215 -b-(gPS) 215 Dissolve in 100 ml of chlorobenzene and mix evenly to obtain a protective coating. The protective coating of the battery box is coated on a stainless steel substrate. After the cyclohexane evaporates, a coating is formed with a thickness of 0.2 mm to obtain sample 5. The coating is observed under a scanning electron microscope (SEM). Figure 3 As shown in (c) and (d), wrinkled strips are formed on the coating surface, and the interior of the strips is porous, and spherical photonic crystals cannot be formed.

[0041] Comparative Example 3 Take 4g of (gPDMS) 215 -b-(gPS) 215 Dissolve in 100 ml of dichloromethane and mix well to obtain a protective coating. The protective coating of the battery box is coated on a stainless steel substrate. After the cyclohexane evaporates, a coating is formed with a thickness of 0.2 mm to obtain sample 6. The coating is observed under a scanning electron microscope (SEM). Figure 3 As shown in (e) and (f), wrinkled strips are formed on the coating surface, and the interior of the strips is porous, and spherical photonic crystals cannot be formed.

[0042] Test example The uncoated stainless steel plate, and the samples of the above embodiments and comparative examples were exposed to sunlight for 30 minutes at 12:00-12:30 in summer, and their surface temperatures were measured. The results are shown in Table 1: Table 1

[0043] It can be seen that the protective coating of the battery box in the present invention can effectively prevent the temperature rise caused by light, and can be applied to the protection of the battery box, while the microspherical photonic crystals in the comparative example cannot be formed and the temperature rise caused by light cannot be prevented. The preparation method of the present invention is relatively simple and low-cost.

[0044] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a protective coating for a battery box, characterized in that: The steps include: Dissolving a block copolymer brush containing PDMS and PS in a side chain in cyclohexane, so that the block copolymer brush containing PDMS and PS in a side chain self-assembles to form microspheres, thereby obtaining the protective coating for a battery box; The structural formula of the block copolymer brush containing PDMS and PS in the side chain is: Wherein x is selected from an integer of 120 to 300, y is selected from an integer of 90 to 250, and the ratio of x to y is 1:0.5 to 2.

2. The method for preparing the protective coating for the battery box according to claim 1, characterized in that: The concentration of the block copolymer brushes containing PDMS and PS on the side chains in cyclohexane was 1-10 g / L.

3. The method for preparing the protective coating for the battery box according to claim 1, characterized in that: In the structural formula of the block copolymer brush containing PDMS and PS in the side chains, x=2.15 and y=2.

15.

4. The method for preparing the protective coating for the battery box according to claim 1, characterized in that: In the structural formula of the block copolymer brush containing PDMS and PS in the side chains, x=148 and y=131.

5. The method for preparing the protective coating for the battery box according to claim 1, characterized in that: In the structural formula of the block copolymer brush containing PDMS and PS in the side chains, x=122 and y=93.

6. The method for preparing the protective coating for the battery box according to claim 1, characterized in that: The particle size of the microspheres is 48-220 nm.

7. The protective coating for a battery box prepared by the method for preparing a protective coating for a battery box according to any one of claims 1 to 6.

8. A method for preparing a battery box coating, characterized in that: The method comprises the following steps: applying the protective coating for the battery box according to claim 7 on the surface of the battery box, and allowing the cyclohexane to volatilize to form a battery box coating.

9. The method for preparing a battery box coating according to claim 8, characterized in that: The thickness of the battery box coating is 0.2~1mm.

10. The battery box coating prepared according to the method for preparing the battery box coating according to claim 8 or 9.

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